Vibration, what vibration?

[alexznam357]

Had my 1982 R65 out today and really tried hard to notice any real vibration issues...and I couldn't. I have a test report from1982 from the British bike mag "On Your Bike" where the tester says:

"Horizontally-opposed engines should be perfectly balanced with both primary and secondary vibrations cancelled out, leaving only a minimal racking couple. But not so the R65LS. It would appear that in their attempt to make the R65 more powerful by revving faster, BMW has produced a rather buzzy motor. Two periods of vibration were evident, one just below 3,000 rpm, the other between 4,250 and 5,000 rpm. At all other engine speeds the motor was as smooth as silk-a fact which simply made its roughness more noticeable. Worse still, at 4,250 rpm the engine is at its most flexible and, in top gear, this figure equates to the UK legal maximium speed. And such a toe-tingling sensation was that it was often preferable to cruise in fourth. As the vibration must be due to some out of balance factor it is surprising that it could not have been "engineered" to occur in part of the rev range where it would have been less intrusive."

Has anyone else noticed this horrible buzziness? Having previously owned a 1976 R90/6, I don't notice much difference between the two (OK...R65 is a little busier due to the gearing and possibly the motor). I will say that the R65 will out handle the longer (and heavier) R90.

[Yikes]

I'm with you, Silver.  That is something I've read about R65's but never noticed any appreciable bands of  vibration on my bike.

[Bob_Roller]

When I first got my R65, back in '81, the vibration band in the 4200 rpm area, was quite pronounced, it was like you had turned a switch on .

But a little over 28 years, and 82,000 miles, I can't detect it anymore, and I swap between the R65, and the R1150R every week, so I think if it was still there, you'd think I would be able to detect it .

Who knows, after 82,000 miles the parts finally got 'wore in', and may be in a better state of balance than they were when new .

[alexznam357]

Hey Bob...any vibration difference between your 1981 R65 and your 1984 LS? When did BMW go to the lightened flywheel, and could that have made a difference in the vibration? How many miles are on your LS, and is it red or silver?

[Bob_Roller]

The '84, is a non-operational bike (got it in late June this year), haven't ridden it, or even started the engine, it's 'the surface of the sun' season here in Phoenix, and I'm just getting started on getting it back to running status .

The lightened flywheel started with the '81 model year, and BMW calls it a 'clutch carrier', not a flywheel .

When you pull your transmission for the first time you'll be amazed, that it is more 'lightning holes' than metal .

[Barry]

My bike has a bit of a buzz at 5000 rpm but it still has very low miles yet and compared to an old British twin you could hardly call it vibration. If I'd just got off my old Bonnie back in the late 70's  I would have thought it to be astonishingly smooth.  The concept of a bike getting smoother  the faster you went would have been almost unbelievable.

[Dave 2]

Sunday I was riding around Acadia National Park's "Auto Roads" where the speed limit is 25-35 MPH. I was usually between 2800 and 3500 RPM in 4th gear. I was real happy as  with the smoothness of my engine. (13,000 Miles).  I Have only put 300 miles or so on this bike and I'm still trying to figure out where the "Vibration" zone are. Compared to my memory of my R60/5 my R65LS has more vibration, but maybe it the short stroke that gives a more pronounced thump that we are feeling?

[montmil]

It never hurts to periodically check the engine mounting bolts; confirm they are torqued to spec. "Things" can loosen up over miles and the years.

Monte

[Bob_Roller]

Hey Bob...any vibration difference between your 1981 R65 and your 1984 LS? When did BMW go to the lightened flywheel, and could that have made a difference in the vibration? How many miles are on your LS, and is it red or silver?

The LS has by my account, with the speedometer being replaced once, and repaired once, and according to the maintenance log that I got with the bike, it has 91,000 miles on it .

It's red, with natural aluminum wheels .

It's a 'well used' bike, but it's been in the desert southwest US all of it's 'life' so it's in pretty good condition, for the miles .

I was hoping to get a red LS with white wheels, but this bike and a red Moto Guzzi 650, presented itself as a 'two for' deal, and after thinking it over for a few days, I came to the conclusion, that this was an opportunity that I shouldn't pass up .

That and the approximately $4000 in spare parts that came with the bikes kind of sealed the deal .

[alexznam357]

Hey Bob...any vibration difference between your 1981 R65 and your 1984 LS? When did BMW go to the lightened flywheel, and could that have made a difference in the vibration? How many miles are on your LS, and is it red or silver?

The LS has by my account, with the speedometer being replaced once, and repaired once, and according to the maintenance log that I got with the bike, it has 91,000 miles on it .

It's red, with natural aluminum wheels .

It's a 'well used' bike, but it's been in the desert southwest US all of it's 'life' so it's in pretty good condition, for the miles .

I was hoping to get a red LS with white wheels, but this bike and a red Moto Guzzi 650, presented itself as a 'two for' deal, and after thinking it over for a few days, I came to the conclusion, that this was an opportunity that I shouldn't pass up .

That and the approximately $4000 in spare parts that came with the bikes kind of sealed the deal .

Wow...4 grand in spares! Did you get alot of the rare LS-only stuff? I'm buying quite a few LS-only spares for my '82, because the day will come when all this stuff is gone...I'll then sell whatever I don't need. What is the overall cond. of your LS? There's an NOS LS seat on Ebay right now for $350...just in case you need it.

[Bob_Roller]

Unfortunately most of the spares are for the Guzzi, I've got two boxes chock full of parts, and I haven't really gone through them yet as well, it's been so hot since I brought the bikes home, that I just started working on the LS on Labor Day Monday, when I removed the entire front brake system .

The seat is in good physical condition, as long as you like sitting on a rock .

I've got a local one man seat refurbishing shop about 8 miles from home, I've had him recover the R65 seat, and the oilhead seat, so it's going to him in about 4 weeks, when I'm on vacation for 5 weeks .

[nhmaf]

The tuning of the engine I have found can have a very significant effect on the vibration band on this bike (82 R65LS) as well as on my 1998 Kawasaki Concours.   On the R65, I get the  valves set at a generous .005"/.009" and adjust the carb balance at idle and to within approx 1 cm Hg @ 4000 RPM.   I get some noticeable vibration from 62 MPH to about 67 MPH in top gear.   As my LS has the very low 32/9 rear end (3.56) ratio, this appears on the tach to be around 4500 - 4800 RPM.   Below or above this, it is quite nice!

The Kawasaki obviously has different valve settings on its 16 valves, but I do set the balance in a similar way, idle and at 4K RPM.  

[steve hawkins]

My 110,000 mile R65 Cafe Racer is as smooth as silk.  Perhaps it like a fine wine that gets better with Age.

Not that I tend to spend a long time at one particular rev range - not being a fan of the Motorway.

Steve H

[Melena]

My bike hadn't had much of a buzz and then I put on the new aftermarket pipes and mufflers.  Now I get more of a buzz but just feel it in my feet.  It only happens around 5000 rpm so I just play with lowering and raising the rpms until I don't notice the buzz any more.  It hasn't been an issue at all

I'm wondering about how the new pipes might affect it.  I can't remember the name, but Justin, I think you have these on your bikes too.  They have only 1 cross over instead of the 2 that the OEM pipes have.  Makes for a more throaty sound.   8-)

[larstorders]

Silver, my current R65 has exactly the same type of high frequebcy buzz in a very narrow rev range over 4000 rpm, which you describe. As it happens, good carb cleanliness and balancing keep the vibes to a perfectly acceptable level. Also, the buzz is limited to a range only about 200 rpm wife, so it's no problem to cruise just above this area.
lower rpm vibes, I find to be quite pleasant on BMs, so no probs there.
My irst R65, which I bought many years ago was A VERY DIFFERENT STORY.
The buzz between 4 and 5 k rpm was absolute torture. Numb fingers were the norm. The bloomin thing was so frustrating, great fun to ride but so painful. If only this forum had existed then to help me out. With suggestions like; careful front wheel balancing, importance of good valve clearances scrupulous carb and jet cleaning and effective carb balancing.
Incidentally,I hear that the newish 800GS twins have a similar annoying buzz ( among a list of other problems which make airheads seem far superior, in terms of reliability).